CN103053040A - Organic el element - Google Patents

Abstract

The invention provides an organic EL element, which can withstand the mass production process of the organic EL display panel, can realize excellent hole injection efficiency, and has high luminous efficiency under low voltage driving. Specifically, an anode (2), a hole injection layer (4), a buffer layer (6A), a light emitting layer (6B), and a cathode (8) are sequentially stacked on one side of a substrate (1) to form an organic EL element (1000) . A bank (5) is formed on the surface of the hole injection layer (4) so as to surround the structure above the buffer layer (6A). The hole injection layer (4) is formed by forming a tungsten oxide thin film by sputtering. At this time, the tungsten oxide film is formed so that in its electronic state, there is an occupied energy level in a binding energy region 1.8 to 3.6 eV lower than the lowest binding energy of the valence band, and the hole injection barrier to the buffer layer is lowered. . Here, a recessed structure is formed in a region defined by the bank (5) in which part of the surface on the functional layer side is located on the anode side rather than other parts, and the recess is covered by a part of the bank. The edge of the constructed recess.

Description

Organic EL

Technical field

The present invention relates to as electroluminescent element organic electroluminescent device (below, be called " organic EL "), relate in particular to the technology that drives with low electric power for the large luminance range in the high briliancy from low briliancy (brightness) to the light source purposes etc.

Background technology

In recent years, use the research and development of the various function element of organic semi-conductor constantly to be made progress.

As representational function element, there is organic EL.Organic EL is the light-emitting component of current drive-type, has following structure: the pair of electrodes that is consisted of by anode and negative electrode between be provided with and comprise the functional layer that organic material forms.Functional layer comprises luminescent layer, resilient coating etc.Sometimes between functional layer and anode, set the hole injection layer for injected hole.Between electrode pair, apply voltage in order to drive, the compound electro optical phenomenon that produces of the electronics that utilizes the hole by being injected into functional layer from anode and be injected into functional layer from negative electrode.Have because carrying out the self-luminous visual identity high and because being the characteristics of complete solid-state components vibration resistance excellence etc., therefore, as the light-emitting component in the various display unit or as the utilization of light source and receive publicity.

Organic EL roughly is divided into two types according to the kind of the functional layer material of using.The first is evaporation type organic EL, and it mainly will hang down molecular material as functional layer material, by vapour deposition method equal vacuum technique this material filming be formed.The second is the coating-type organic EL, and its low molecular material that macromolecular material or film-shaped are become second nature forms this material filming as functional layer material by wet processings such as ink-jet method or heliogravure (gravure) print processes.

Up to the present, because the reasons such as the luminous efficiency of luminescent material is high, the driving life-span is long, the exploitation of evaporation type organic EL is leading (for example, with reference to patent documentation 1,2) comparatively, begun practical at mobile phone with aspects such as display, minitelevisions.

Evaporation type organic EL is suitable for the purposes of small-sized organic EL panel, but panchromatic (full color, colour) the large-scale organic EL panel that for example is applied to 100 inches levels is very difficult.Its main cause is manufacturing technology.In the situation that use evaporation type organic EL to make organic EL panel, generally respectively by each color (for example R, G, B(red, green, blue)) use mask evaporation method when coming the film forming luminescent layer.But, when the panel area is large, because the difference of the thermal coefficient of expansion of mask and glass substrate etc. are difficult to guarantee the positioning accuracy of mask, so can't make normal display.In order to overcome these problems, have at whole luminescent layer material that uses white, RGB colour filter (colour filter) is set avoids the method for making respectively, but in this case, the light of taking-up is 1/3 of luminous quantity, so the shortcoming that exists power consumption to increase on the principle.

So, for the maximization of this organic EL panel, begin to attempt realizing with the coating-type organic EL.As mentioned above, in the coating-type organic EL, make functional layer material by wet processing.In this technique, the positional precision during coating functional layer does not rely on substrate size basically respectively in the precalculated position, therefore has advantages of for the technology barrier that maximizes low.

On the other hand, also the prevailing research and development of the luminous efficiency that improves organic EL.In order to make organic EL luminous with high efficiency, low-power consumption and high brightness, injected carrier (hole and electronics) is important efficiently from electrode to functional layer.Generally, charge carrier is injected efficiently, the implanted layer of the energy barrier (energy barrier) when being provided for reducing injection between each electrode and functional layer is effective.Wherein, as hole injection layer, use with CuPc, molybdenum oxide as coated film such as the vapor-deposited film of representative and/or PEDOT.Have report to point out: especially in using the organic EL of molybdenum oxide, hole injection efficiency improves, the life-span improve (for example with reference to patent documentation 3).

The prior art document

Patent documentation 1: No. 3369615 communiques of Japan's special permission

Patent documentation 2: No. 3789991 communiques of Japan's special permission

Patent documentation 3: TOHKEMY 2005-203339 communique

Non-patent literature 1:Jingze Li et al., Synthetic Metals151,141(2005)

Non-patent literature 2: cross hem width own, other, the 7th regular meeting preliminary draft collection of organic EL discussion, 17(2008)

Non-patent literature 3:Hyunbok Lee et al., Applied Physics Letters93,043308(2008)

Non-patent literature 4: Junichiro Koizumi strong two other, the 56th time applied physics concerns associating oratorical contest preliminary draft collection, 30p-ZA-11(2009)

Non-patent literature 5: middle mountain is safe gives birth to other, the 7th regular meeting preliminary draft collection of organic EL discussion, 5(2008)

Summary of the invention

The problem that invention will solve

Yet, in having the coating-type organic EL of above-mentioned advantage, require than the better low voltage drive of present situation and raising luminous efficiency.Particularly, in the situation that make the coating-type organic EL, require the further improvement of hole injection efficiency and the further improvement in life-span.

The present invention is the invention of finishing in view of above problem, and purpose is to provide a kind of organic EL, and the hole injection barrier between its hole injection layer and the functional layer is low, can bring into play excellent hole injection efficiency, can expect good low voltage drive thus.

For the means of dealing with problems

In order to address the above problem, the structure of a kind of mode of the present invention is, possesses: anode; Negative electrode; Functional layer, it is configured between described anode and the described negative electrode, by comprising that 1 layer of using luminescent layer that organic material forms or multilayer consist of; Hole injection layer, it is configured between described anode and the described functional layer; Dike with the described luminescent layer of regulation, described hole injection layer comprises tungsten oxide, can have occupied level in the zone at minimum than valence band in conjunction with the combination that can hang down 1.8～3.6eV, described hole injection layer forms the part on the surface of described functional layer side and compares the depression structure that more is positioned at described anode one side with other parts in the zone by described dike regulation, the edge of the recess in the described depression structure is covered by the part of described dike.

The effect of invention

In the organic EL of a kind of mode of the present invention, hole injection layer constitutes and comprises tungsten oxide.Further, this hole injection layer constitutes in its electronic state and can have occupied level in the zone at minimum than valence band in conjunction with the combination that can hang down 1.8～3.6eV.Owing to having this occupied level, the hole injection barrier between hole injection layer and the functional layer can be suppressed less.Its result, the hole injection efficiency of the organic EL of a kind of mode of the present invention is high, can drive with low-voltage, and can expect the luminous efficiency that performance is excellent.

Yet, in the situation that hole injection layer is made of the tungsten oxide with above-mentioned predetermined occupied level, can be created in that the thickness of hole injection layer reduces in the manufacturing process (below, be designated as " film minimizing ") peculiar and new problem, might cause to be exerted an influence to the characteristics of luminescence by the luminance nonuniformity in the illuminating part face in the zone of dike regulation and/or the reduction of component life etc.

Relative therewith, in the organic EL of above-mentioned a kind of mode of the present invention, hole injection layer forms the part on the surface of functional layer side and compares the depression structure that more is positioned at anode one side with other surface portion, and then, because the edge of the depression of hole injection layer structure is covered by the part of dike, concentrate so can relax the electric field of this edge part.Thus, can prevent the generation of the problems such as reduction of luminance nonuniformity and component life, the generation on the impact of the characteristics of luminescence can be prevented trouble before it happens.

Description of drawings

Fig. 1 is the schematic sectional view of the structure of the organic EL that relates to of expression execution mode.

Fig. 2 is the schematic sectional view of the structure of the single hole of expression element.

Fig. 3 is that the driving voltage of the single hole of expression element is for the dependent coordinate diagram of the membrance casting condition of hole injection layer.

Fig. 4 is the device property figure of the relation curve that applies voltage and current density of the single hole of expression element.

Fig. 5 is the device property figure of the relation curve that applies voltage and current density of the organic EL made of expression.

Fig. 6 is the device property figure of the relation curve of the current density of the organic EL made of expression and luminous intensity.

Fig. 7 is the schematic sectional view of the structure of the sample used of expression photoelectron spectroscopic measurements.

Fig. 8 is the figure of the UPS spectrum of expression tungsten oxide.

Fig. 9 is the figure of the UPS spectrum of expression tungsten oxide.

Figure 10 is the figure of differential curve of the UPS spectrum of presentation graphs 9.

Figure 11 is the figure of UPS spectrum that expression is exposed to the tungsten oxide of atmosphere.

Figure 12 merges the UPS spectrum of expression tungsten oxide of the present invention and the figure of XPS spectrum.

Figure 13 is the interfacial energy diagram of tungsten oxide and α-NPD.

Figure 14 is the figure for the effect of the injection phase of explanation hole injection layer and functional layer.

Figure 15 is the coordinate diagram of the relation of the expression film reduction of hole injection layer and film density.

Figure 16 is the cutaway view that obtains the process of a kind of mode of the present invention for explanation.

Figure 17 is the vertical view of the part of the OLED display that relates to of expression embodiment of the present invention 2.

Figure 18 is the cutaway view that schematically illustrates a part of section of the OLED display that embodiment of the present invention 2 relates to.

Figure 19 is the amplification view of the B section that is surrounded by single-point line among Figure 18.

Figure 20 is the process chart of the manufacture method of the OLED display that relates to of explanation embodiment of the present invention 2.

Figure 21 is the process chart of the manufacture method of the OLED display that relates to of explanation embodiment of the present invention 2.

Figure 22 is the process chart of the manufacture method of the OLED display that relates to of explanation embodiment of the present invention 2.

Figure 23 is the cutaway view that schematically illustrates a part of section of the OLED display that variation of the present invention relates to.

Figure 24 is the process chart of the manufacture method of the OLED display that relates to of explanation variation of the present invention.

Figure 25 is the cutaway view that schematically illustrates a part of section of the OLED display that variation of the present invention relates to.

Figure 26 is the vertical view of the part of the OLED display that relates to of expression variation of the present invention.

Figure 27 is the cutaway view of the part of the OLED display that relates to of expression variation of the present invention.

Label declaration

The 1TFT substrate; 2 anodes; The 3ITO(tin indium oxide) layer; 4 hole injection layers (tungsten oxide layer); The 4a recess; The bottom surface of 4b recess; The edge of 4c recess; The side of 4d recess; The top zone of not caving in of 4e hole injection layer; 5 dikes; The bottom surface of 5a, 5b dike; The horizontal plane of the bottom surface of 5c dike; 5d covering section; The 6A resilient coating; The 6B luminescent layer; 7 electron injecting layers; 8 negative electrodes; 8A barium layer; The 8B aluminium lamination; 9 envelopes are ended layer; 10 substrates; 10a, 10b, 10c organic EL; 11 films; 12 dike material layers; 13 hole transporting layers; 55 pixel dikes; 55a dyke part; 55b dyke part; 56a1,56a2,56b1,56b2,56c1,56c2 luminescent layer; 65 line dikes; 66a, 66b, 66c luminescent layer; 70 conductivity silicon substrates; 80 tungsten oxide layer; 100 OLED display; 1000 organic ELs; 1000A photoelectron spectral photometry sample; The single hole of 1000B element.

Embodiment

The organic EL of a kind of mode of the present invention possesses: anode; Negative electrode; Functional layer, it is configured between described anode and the described negative electrode, by comprising that 1 layer of using luminescent layer that organic material forms or multilayer consist of; Hole injection layer, it is configured between described anode and the described functional layer; Dike with the described luminescent layer of regulation, described hole injection layer comprises tungsten oxide, can have occupied level in the zone at minimum than valence band in conjunction with the combination that can hang down 1.8～3.6eV, described hole injection layer forms the part on the surface of described functional layer side and compares the depression structure that more is positioned at described anode one side with other parts in the zone by described dike regulation, the edge of the recess in the described depression structure is covered by the part of described dike.

In addition, as another kind of mode of the present invention, can be because of there being described occupied level, at the stacked interface of described hole injection layer and described functional layer, the combination of the highest occupied orbital of described functional layer can be positioned in described occupied level in conjunction with can near.

In addition, as another kind of mode of the present invention, at the stacked interface of described hole injection layer and described functional layer, the combination of described occupied level can with the highest occupied orbital of described functional layer in conjunction with can difference can be in ± 0.3eV.

In addition, as another kind of mode of the present invention, in UPS spectrum, described hole injection layer can be minimum than valence band in conjunction with hang down the bossed shape of tool in 1.8～3.6eV regional in conjunction with energy.

In addition, in XPS spectrum, described hole injection layer can be minimum than valence band in conjunction with hang down the bossed shape of tool in 1.8～3.6eV regional in conjunction with energy.

In addition, as another kind of mode of the present invention, in the differential smoothing of UPS spectrum, described hole injection layer can have the shape that shows as the function different from exponential function in the whole combination energy zone in conjunction with can hang down 2.0～3.2eV minimum than valence band.

In addition, as another kind of mode of the present invention, described functional layer can comprise the amine based material.

In addition, as another kind of mode of the present invention, described functional layer can be to carry the hole transporting layer in hole and be used for the adjustment optical characteristics or at least either party of the resilient coating of the purposes of obstruction electronics.

In addition, as another kind of mode of the present invention, the described occupied level of described hole injection layer may reside in the combination minimum than valence band and can hang down in the combination energy zone of 2.0～3.2eV.

In addition, as another kind of mode of the present invention, can reach for: the part of described dike the recess bottom surface of the depression structure of described hole injection layer, the side of described dike is up inclined-plane to the limit from the point of arrival that arrives described recess bottom surface.

In addition, as another kind of mode of the present invention, the part of described dike can not arrive the recess bottom surface of the depression structure of described hole injection layer.

In addition, as another kind of mode of the present invention, described hole injection layer can extend to the side of described dike along the bottom surface of described dike.

In addition, as another kind of mode of the present invention, the salient angle part that the edge of the described recess of described hole injection layer can form for the side by the top zone of not caving in of described hole injection layer and described recess.

In addition, as another kind of mode of the present invention, can for: described dike has liquid repellency, and described hole injection layer has lyophily.。

In addition, as another kind of mode of the present invention, can possess above-mentioned organic EL as the display unit of a kind of mode of the present invention.

In addition, as another kind of mode of the present invention, manufacture method as the organic EL of a kind of mode of the present invention, comprise: the 2nd operation, to described anode film forming tungsten oxide layer, to be used as the gas in the sputtering chamber of sputter equipment by the gas that argon gas and oxygen consist of, the stagnation pressure of described gas for greater than 2.7Pa and below the 7.0Pa, the ratio of oxygen partial pressure and stagnation pressure is more than 50% and below 70% and the input power density of target per unit area is 1W/cm ²Above and 2.8W/cm ²The described tungsten oxide layer of film forming under the following membrance casting condition; The 3rd operation forms the dike material layer that is formed by the material that consists of dike in described tungsten oxide layer; The 4th operation, remove the part of described dike material layer, the part of described tungsten oxide layer is exposed, the top part of described tungsten oxide layer is compared with other top parts more be positioned at described anode one side, form have inner bottom surface and with the depressed part of the continuous medial surface of described inner bottom surface; The 5th operation by implementing heat treatment to residual of the described dike material layer on the described tungsten oxide layer, is given flowability to the residual section of described dike material layer, makes the material that consists of described dike extend to the edge of the recess of described depressed part from described residual section; The 6th operation after described heat treatment step, forms the functional layer that comprises luminescent layer in the described tungsten oxide layer of exposing; And the 7th operation, above described functional layer, form negative electrode.

In addition, as another kind of mode of the present invention, in the manufacture method as the organic EL of a kind of mode of the present invention, can pass through in described the 2nd operation, with described tungsten oxide layer film forming be: its UPS spectrum is the bossed shape of tool in the combination energy in conjunction with can hang down 1.8～3.6eV minimum than valence band is regional.

In addition, as another kind of mode of the present invention, in the manufacture method as the organic EL of a kind of mode of the present invention, can be with described tungsten oxide layer film forming: the differential smoothing of its UPS spectrum whole than valence band minimum have the shape that shows as the function different from exponential function in conjunction with what can hang down 2.0～3.2eV in conjunction with energy is regional.

Below, the organic EL of embodiment of the present invention is described, then narrate result and the investigation of each confirming performance experiment of the present invention.

Scale of components chi in each accompanying drawing is from actual different.

＜execution mode 1 〉

(structure of organic EL)

Fig. 1 is the schematic sectional view of structure of the organic EL 1000 of expression present embodiment.

Organic EL 1000 is coating-type elements of making by the wet processing coating functional layer, have following structure: between the electrode pair that is made of anode 2 and negative electrode 8, described various functional layers are to comprise the organic material with predetermined function to form under mutually stacked state for hole injection layer 4 and various functional layer (being resilient coating 6A and luminescent layer 6B at this).

Particularly, as shown in Figure 1, organic EL 1000 is for a side interarea of substrate 1 in the following order stacked anode 2, hole injection layer 4, resilient coating 6A, luminescent layer 6B, negative electrode 8(barium layer 8A and aluminium lamination 8B) and consist of.

Substrate 1 is such as using soda-lime glass (soda glass), being that glass, quartz, propylene resin (acrylic resin), phenylethylene resin series, polycarbonate-based resin, epoxy are that resin, polyethylene, polyester, silicon are that the insulating properties materials such as resin or aluminium oxide (alumina) consist of without fluorescent glass, phosphate glass, boric acid.Be formed with predetermined TFT wiring on the surface of one side.

Anode 2 can be by the alloy such as APC(silver, palladium, copper), the alloy of ARA(silver, rubidium, gold), the alloy of MoCr(molybdenum and chromium), the alloy of NiCr(nickel and chromium) etc. form.In the situation of the light-emitting component of top emission structure, preferably the material by highly reflective forms.

(hole injection layer)

Hole injection layer 4 is formed by the tungsten oxide film (layer) of thickness 30nm.In its composition formula (WOx), x is the real number in the scope of 2＜x＜3 roughly.

Hole injection layer 4 preferably only is made of tungsten oxide as far as possible, but also can contain the impurity of the denier of the degree that can sneak under the common level.

At this, this hole injection layer 4 is film forming under specific membrance casting condition.Thus, in its electronic state, in the upper end of valence band (valence band), namely than valence band minimum in conjunction with the combination energy region memory that can hang down 1.8～3.6eV at occupied level.This occupied level is equivalent to the highest occupied level of hole injection layer 4, that is, its in conjunction with energy range near the Fermi surface (Fermi Surface) of hole injection layer 4.Therefore, below this occupied level is called " near the occupied level the Fermi surface ".

Owing to there being near the occupied level this Fermi surface, stacked interface in hole injection layer 4 and functional layer (be resilient coating 6A at this) has realized that so-called interface energy level is continuous, the combination of the highest occupied orbital of resilient coating 6A can with the described Fermi surface of hole injection layer 4 near the combination of occupied level can be about equally.

Refer in this said " about equally " and " having realized that interface energy level is continuous ": at hole injection layer 4 and resilient coating 6A at the interface, near the minimum combination of the occupied level the described Fermi surface can with the highest described occupied orbital minimum in conjunction with can difference ± 0.3eV with interior scope in.

Further, refer at this said " interface ": comprise hole injection layer 4 the surface and apart from the zone of this surface 0.3nm with the resilient coating 6A of interior distance.

In addition, near the occupied level the described Fermi surface preferably is present in whole hole injection layer 4, but the interface that is present at least with resilient coating 6A gets final product.

(dike)

Be formed with the dike 5 that is formed by the organic material of insulating properties (be resin, phenolic varnish type phenol resin etc. such as propylene resin, polyimides) on the surface of hole injection layer 4, so that form lines (stripe) structure or the groined type structure with certain trapezoidal cross-section.Be formed with functional layer on the surface by the hole injection layer 4 of each dike 5 zoning, described functional layer comprises resilient coating 6A and the luminescent layer 6B corresponding with any one color among the RGB.As shown in Figure 1, in the situation that organic EL 1000 is applied to organic EL panel, with with of all kinds corresponding a series of 3 elements 1000 of RGB as 1 unit (pixel, pixel), these a series of 3 elements 1000 of a plurality of units of spread configuration on substrate 1.

In addition, dike 5 is not structure necessary among the present invention, does not need dike 5 in as situations such as monomer use organic ELs 1000.

(resilient coating)

Resilient coating 6A is organic macromolecule TFB(poly(9 by thickness 20nm's as amine, 9-di-n-octylfluorene-alt-(1,4-phenylene-((4-sec-butylphenyl) imino)-Isosorbide-5-Nitrae-phenylene)) consist of.

(luminescent layer)

Luminescent layer 6B by thickness 70nm as organic macromolecule F8BT(poly(9,9-di-n-octylfluorene-alt-benzothiadiazole)) consist of.But luminescent layer 6B is not limited to the structure that is made of this material, can constitute to comprise known organic material.For example, can list class oxine (oxinoid) compound, perylene compound, coumarin compound, azepine coumarin compound, oxazole compounds, oxadiazole compound, purple cyclic ketones (perinone) compound, pyrrolopyrrole compound, naphthalene compound, anthracene compound, fluorene compound, fluoranthene compound, aphthacene compound, pyrene compound, coronene compound, quinolone compounds and azepine quinolone compounds, pyrazoline derivative and pyrazolone derivative that Japanese kokai publication hei 5-163488 communique puts down in writing, rhodamine compound,

(chrysene) compound, phenanthrene compound, cyclopentadiene compound, stilbene compounds, the diphenyl benzene naphtoquinone compounds, compound of styryl, adiene cpd, two cyanogen methylene pyrylium compounds, two cyanogen methylene thiapyran compounds, Fluorescein compound, pyrylium compound, the thiapyran compound, the selenium pyrylium compound, the tellurium pyrylium compound, aromatic series canrenone compound, low polyphenylene compound, the thioxanthene compound, the anthocyanin compound, acridine compounds, the metal complex of oxine compound, 2, the metal complex of 2 '-Bipyridine compound, the complex of schiff bases and III family metal, oxine (oxine) metal complex, the fluorescent materials such as terres rares complex etc.

(functional layer)

Functional layer among the present invention refers to carry the hole transporting layer in hole, luminous luminescent layer, be used for any one or the combination of two-layer above these layers or all layers of the resilient coating etc. of the purposes adjusting optical characteristics or hinder electronics by institute's injected holes and electron recombination.The present invention is take hole injection layer as object, but also there is the layer of bringing into play separately required function of above-mentioned hole transporting layer, luminescent layer etc. in organic EL except hole injection layer.Functional layer refers to as the required layer of the organic EL beyond the hole injection layer of object of the present invention.

(other electrodes, substrate etc.)

The barium layer 8A of negative electrode 8 stacked thickness 5nm and the aluminium lamination 8B of thickness 100nm consist of.

Be connected with power supply 11 at anode 2 and negative electrode 8, power from the outside to organic EL 1000.

Substrate 1 can be that glass, quartz, propylene resin, phenylethylene resin series, polycarbonate-based resin, epoxy are that resin, polyethylene, polyester, silicon are that arbitrary material in the insulating properties materials such as resin or aluminium oxide forms by alkali-free glass, soda-lime glass, without fluorescent glass, phosphate glass, boric acid.

(effect of organic EL)

In the organic EL 1000 with above structure, because near the occupied level there is described Fermi surface in hole injection layer 4, and the hole injection barrier between the resilient coating 6A is little.Therefore, when when driving, organic EL 1000 being applied voltage, can be with low-voltage and near the occupied level the described Fermi surface of hole from hole injection layer 4 is injected to the highest occupied orbital of resilient coating 6A, can bring into play the high hole injection efficiency.

For the structure itself that tungsten oxide is used as hole injection layer, there had been report (with reference to non-patent literature 1) in the past.But the thickness of the hole injection layer of the best that obtains in this report is about 0.5nm, and the thickness dependence that affects voltage-current characteristic is also larger, to the not enlightenment of practicality of the large-scale organic EL panel degree of volume production.Further, do not enlighten near hole injection layer forms Fermi surface energetically occupied level yet.The present invention and the prior art part that differs widely is, stable by chemistry and also tolerate in the hole injection layer that the tungsten oxide of the batch production technique of large-scale organic EL panel forms, there is near the occupied level of predetermined Fermi surface, obtain thus excellent hole injection efficiency, in organic EL, realized low voltage drive.

Then, the manufacture method of illustration organic EL 1000 integral body.

(manufacture method of organic EL)

At first, substrate 1 is loaded in the sputtering chamber of spattering filming device.Then, to the predetermined sputter gas of indoor importing, by the anode 2 that is formed by ITO of reactive sputtering method film forming thickness 50nm.

Then, film forming hole injection layer 4 preferably comes film forming by the reactive sputtering method.Particularly the large-scale organic EL panel that needs the large tracts of land film forming is being used in the situation of the present invention, when carrying out film forming by vapour deposition method etc., might caused thickness etc. to produce irregular.When carrying out film forming by the reactive sputtering method, then easily avoid producing such film forming irregular.

Particularly, target is replaced with tungsten, implement the reactive sputtering method.In sputtering chamber, import argon gas as sputter gas, import oxygen as reactant gas.Under this state, with argon ion, make it collide target by high voltage.At this moment, tungsten and the oxygen reaction of emitting by sputtering phenomenon become tungsten oxide, and film forming is on the anode 2 of substrate 1.

This membrance casting condition as described later, air pressure (stagnation pressure) is greater than 2.7Pa and below the 7.0Pa, oxygen partial pressure is more than 50% and below 70% with the ratio of stagnation pressure, and the input electric power of target per unit area (dropping into power density (input power density)) is preferably set to 1W/cm ²Above and 2.8W/cm ²Below.Form hole injection layer 4 through this operation, described hole injection layer 4 can have occupied level in the zone at minimum than valence band in conjunction with the combination that can hang down 1.8～3.6eV.

Then, as the dike material, prepare photosensitive anticorrosive additive material for example, preferably contain the photo anti-corrosion agent material of fluorine based material.On hole injection layer 4, apply equably this dike material, after the prebake, overlapping mask with peristome (pattern of the dike that will form) of reservation shape.Then, after the mask top makes its sensitization, wash out uncured unnecessary dike material with developer solution.Clean with pure water at last, thereby finish dike 5.

At this, in the present embodiment, hole injection layer 4 is made of the tungsten oxide that aqueous slkali, water, organic solvent etc. is had tolerance.Therefore, form in the operation at dike, even the hole injection layer that has formed 4 contacts with this solution, pure water etc., also can suppress the damage that is caused by dissolve, go bad, decomposition etc.Like this, by keeping the form of hole injection layer 4, also can after organic EL 1000 is finished, carry out efficiently the hole via this hole injection layer 4 to resilient coating 6A and inject, can realize well low voltage drive.

Then, by the wet processing of for example ink-jet method or gravure processes, drip and contain the constituent China ink that amine is organic molecule material in the surface of the hole injection layer 4 that exposes between adjacent dike 5, makes solvent evaporates and solvent is removed.Form thus resilient coating 6A.

Then, the constituent China ink that using the same method on the surface of resilient coating 6A drips contains luminous organic material makes solvent evaporates and solvent is removed.Form thus luminescent layer 6B.

The formation method of resilient coating 6A, luminescent layer 6B is not limited to this, also can drip, apply China ink by method, the known methods such as a minute method of the use of ink and water, nozzle coating process, spin-coating method, intaglio printing, letterpress beyond ink-jet method, the gravure processes.

Then, come film forming barium layer 8A, aluminium lamination 8B on the surface of luminescent layer 6B by vacuum vapour deposition.Thus, form negative electrode 8.

Although not shown among Fig. 1, be exposed to atmosphere as purpose to suppress organic EL 1000, envelope can also be set on the surface of negative electrode 8 end layer, perhaps setting spatially makes element 1000 whole envelopes with external isolation end tank.Envelope is ended layer can be by such as the SiN(silicon nitride), the SiON(silicon oxynitride) etc. material forms, be arranged to only element 1000 of inner envelope.In the situation that use envelope to end tank, envelope is ended tank for example can by forming with the same material of substrate 1, arrange the getter (getter) that adsorbed water is graded in confined space.

Through above operation, finish organic EL 1000.

＜various experiments and investigation 〉

(about the membrance casting condition of tungsten oxide)

In the present embodiment, consist of the tungsten oxide of hole injection layer 4 by film forming under predetermined membrance casting condition, make hole injection layer 4 have near the occupied level of above-mentioned Fermi surface, reduce the hole injection barrier between hole injection layer 4 and the resilient coating 6A, make it possible to organic EL 1000 is carried out low voltage drive.

As the film build method for the tungsten oxide that obtains such performance, consideration is suitable to be set following membrance casting condition for and comes film forming by the reactive sputtering method, that is: use the DC magnetic controlled tube sputtering apparatus, target is tungsten, substrate temperature is not controlled, the sputter indoor gas is made of argon gas and oxygen, air pressure (stagnation pressure) is greater than 2.7Pa and below the 7.0Pa, oxygen partial pressure is more than 50% and below 70% with the ratio of stagnation pressure, and the input electric power of target per unit area (input power density) is 1W/cm ²Above and 2.8W/cm ²Below.

The validity of above-mentioned membrance casting condition has obtained affirmation by following each experiment.

At first, in order to estimate effectively the membrance casting condition dependence of the hole injection efficiency from hole injection layer 4 to resilient coating 6A, as estimating device, made single hole element.

In organic EL, the charge carrier that forms electric current be hole and electronics the two, therefore, on the electrical characteristics of organic EL, except hole current, also reflecting electronic current.But in the element of single hole, owing to being obstructed from the injection of the electronics of negative electrode, so mobile electron electric current hardly, all electric currents roughly only are made of hole current, and namely charge carrier is regarded as roughly only being the hole, is fit to estimate hole injection efficiency.

Concrete single hole element of making is the element that the negative electrode 9 as shown in Figure 2 of the negative electrode 8 in the organic EL 1000 of Fig. 1 is replaced as like that gold.Namely, as shown in Figure 2, form the anode 2 that the ito thin film by thickness 50nm forms at substrate 1, further anode 2 stack gradually hole injection layer 4 that the tungsten oxide by thickness 30nm forms, by thickness 20nm as amine be the resilient coating 6A that forms of organic macromolecule TFB, the negative electrode 9 that forms by the luminescent layer 6B that forms as organic macromolecule F8BT of thickness 70nm, by the gold of thickness 100nm.Owing to being to estimate device, so omitted dike 5.

In this production process, hole injection layer 4 usefulness DC magnetic controlled tube sputtering apparatus and come film forming by the reactive sputtering method.The sputter indoor gas is made of at least a of argon gas and oxygen, and target has used tungsten.Substrate temperature is not controlled, and partial pressure of ar gas, oxygen partial pressure, stagnation pressure are regulated with the flow of each gas.Membrance casting condition is shown in following table 1, and each condition that makes stagnation pressure, oxygen partial pressure and drop into electric power (access power) changes, and obtains thus possessing single hole element 1000B(element No.1 of the hole injection layer 4 of film forming under each membrance casting condition～14).After this, oxygen partial pressure is expressed as the ratio (%) with stagnation pressure.

［ table 1 ］

The membrance casting condition of each single hole element 1000B

Element No.	1	2	3	4	5	6	7	8	9	10	11	12	13	14
															Oxygen partial pressure (%)	70	50	100	50	70	100	70	50	100	50	70	30	30	50
Stagnation pressure (Pa)	2.7	4.8	1.7	1.7	2.7	1.7	2.7	4.8	1.7	2.7	1.7	1.7	2.7	4.8
															Drop into electric power (W)	500	500	500	500	250	250	1000	1000	1000	500	500	500	500	250
T-S(mm)	113	113	113	113	113	113	113	113	113	113	113	113	113	113
															Rate of film build (nm/s)	0.164	0.14	0.111	0.181	0.057	?	0.308	0.311	0.246	0.154	0.153	0.364	0.177	0.049
Thickness (nm)	30	30	30	30	30	30	30	30	30	30	30	30	30	30

The input electric power of above-mentioned DC magnetic controlled tube sputtering apparatus shown in the table 2 and the relation that drops into power density.

［ table 2 ］

Drop into electric power (W)	Drop into power density (W/cm 2）
		250	1.4
500	2.8
		1000	5.6

Each the single hole element 1000B that makes is connected with DC power supply DC, and has applied voltage.Make the change in voltage that applies of this moment, will be converted into the current value that magnitude of voltage correspondingly flows the value (current density) of the per unit area of element.Below, " driving voltage " is made as current density is 10mA/cm ²The time apply voltage.

Can say that this driving voltage is less, the hole injection efficiency of hole injection layer 4 is higher.Reason is thought and is, in each single hole element 1000B, because the manufacture method at each position beyond the hole injection layer 4 is identical, so the hole injection barrier between two the adjacent layers except hole injection layer 4 is certain.In addition, by other experimental verifications the negative electrode 2 that uses in should experiment are connected with hole injection layer and connect for ohm.The difference of the driving voltage that therefore, is caused by the membrance casting condition of hole injection layer 4 has reflected the hole injection efficiency from hole injection layer 4 to resilient coating 6A forcefully.

Table 3 is values with respect to the driving voltage of each membrance casting condition of stagnation pressure, oxygen partial pressure, input electric power of each single hole element 1000B of obtaining by this experiment.In the table 3, the element number (No.) of each single hole element 1000B represents with the circle numeral.

［ table 3 ］

The membrance casting condition of each single hole element 1000B and driving voltage (current density 10mA/cm ²The time apply magnitude of voltage)

* the circle numeral is element number, and the outer numerical value of parantheses is to drop into electric power, and the numerical value in the parantheses is driving voltage

In addition, Fig. 3 (a)～(c) is the dependent coordinate diagram of membrance casting condition that gathers the driving voltage of each single hole element 1000B.Each point in Fig. 3 (a) represents element No.4,10,2 driving voltage from left to right.Each point in Fig. 3 (b) represents element No.13,10,1 driving voltage from left to right.Have, the each point in Fig. 3 (c) represents element No.14,2,8 driving voltage from left to right again.

In this experiment, in the situation that stagnation pressure is 2.7Pa and oxygen partial pressure is 100%, stagnation pressure is that 4.8Pa and oxygen partial pressure are in 30% the situation, stagnation pressure is that 4.8Pa and oxygen partial pressure are in 70% the situation, stagnation pressure is that 4.8Pa and oxygen partial pressure are in 100% the situation, all can not carry out film forming owing to the restriction of the sputter equipments such as gas flow.

At first, for the stagnation pressure dependence of driving voltage, as from Fig. 3 (a) as can be known, at oxygen partial pressure 50%, drop under the condition of electric power 500W, at least stagnation pressure be greater than 2.7Pa and the scope below the 4.8Pa in, can confirm the clear and definite decline of driving voltage.By other experiments as can be known, this tendency lasts till that at least stagnation pressure is the following scope of 7.0Pa.Therefore, can say that stagnation pressure preferably sets in greater than 2.7Pa and the scope below the 7.0Pa.

Then, for the oxygen partial pressure dependence of driving voltage, as from Fig. 3 (b) as can be known, be 2.7Pa at stagnation pressure, to drop into electric power be under the condition of 500W, at least in oxygen partial pressure is scope more than 50% and below 70%, can confirm the rising of oxygen partial pressure and the decline of driving voltage.But, when oxygen partial pressure rises to above-mentioned scope when above, can confirm driving voltage by other experiments and rise on the contrary.Therefore, can say that oxygen partial pressure is preferably more than 50% and with the upper limit is suppressed at about 70%.

Then, for the input electric power dependence of driving voltage, as from Fig. 3 (c) as can be known, be that 4.8Pa, oxygen partial pressure are under 50% the condition at stagnation pressure, can confirm that driving voltage sharply rises when dropping into electric power and surpassing 500W.Therefore, think that dropping into electric power preferably suppresses for below the 500W.As the element No.1 that observes table 3,3 the time, can confirm following result: even input electric power is 500W, when stagnation pressure is below the 2.7Pa, driving voltage also can rise.

Then, Fig. 4 shows among each single hole element 1000B the voltage curve as the element No.14,1 of representative, 7 current density-apply.The longitudinal axis is current density (mA/cm among the figure ²), transverse axis is for applying voltage (V).Element No.14 satisfies whole optimum condition of above-mentioned stagnation pressure, oxygen partial pressure, input electric power.On the other hand, element No.1,7 does not satisfy the part of above-mentioned optimum condition.

At this, for the following description, for hole injection layer 4(and tungsten oxide layer described later 80) membrance casting condition, the membrance casting condition of element No.14 is called membrance casting condition A, the membrance casting condition of element No.1 is called membrance casting condition B, the membrance casting condition of element No.7 is called membrance casting condition C.In addition, correspondingly, also element No.14 being recorded and narrated in Fig. 4 and table 3 is HOD-A, element No.1 is recorded and narrated be HOD-B, element No.7 is recorded and narrated be HOD-C.

As shown in Figure 4, HOD-A compares with HOD-B, HOD-C, and the rising of current density-apply voltage curve in addition, can obtain high current density with the minimum voltage that applies the earliest.That is, HOD-A compares with HOD-B, HOD-C, and hole injection efficiency is obviously excellent.HOD-A is the minimum element of driving voltage among each single hole element 1000B.

More than be the checking relevant with the hole injection efficiency of hole injection layer 4 among single hole element 1000B, the structure of single hole element 1000B is identical with the organic EL 1000 of Fig. 1 except negative electrode.Therefore, in organic EL 1000, the membrance casting condition dependence of the hole injection efficiency from hole injection layer 4 to resilient coating 6A is also identical with single hole element 1000B in essence.In order to confirm this situation, made each organic EL 1000 that uses the hole injection layer 4 under membrance casting condition A, B, the C.

The structure 1 of concrete each organic EL of making as shown in Figure 1, form the anode 2 that the ito thin film by thickness 50nm forms at substrate 1, further anode 2 stack gradually hole injection layer 4 that the tungsten oxide by thickness 30nm forms, by thickness 20nm as amine be the resilient coating 6A that forms of organic macromolecule TFB, the negative electrode 8 that forms by the luminescent layer 6B that forms as organic macromolecule F8BT of thickness 70nm, by the aluminium of the barium of thickness 5nm and thickness 100nm.Owing to being to estimate device, so omitted dike 5.

Membrance casting condition A, the B that makes, each organic EL 1000 under the C are connected with DC power supply DC, and have applied voltage.The current density of the relation when the applying voltage and will be converted into the current value that each magnitude of voltage correspondingly flows the value of per unit area of element of expression this moment has been shown among Fig. 5-apply voltage curve.The longitudinal axis is current density (mA/cm among the figure ²), transverse axis is to apply voltage (V).

For the following description, in Fig. 5 the organic EL 1000 of membrance casting condition A being recorded and narrated is BPD-A, the organic EL 1000 of membrance casting condition B is recorded and narrated be BPD-B, the organic EL 1000 of membrance casting condition C is recorded and narrated be BPD-C.

As shown in Figure 5, BPD-A compares with BPD-B, BPD-C, and the rising of current density-apply voltage curve in addition, can obtain high current density with the minimum voltage that applies the earliest.This be with as the same tendency of HOD-A, HOD-B, the HOD-C of the single hole element under each identical membrance casting condition.

Further, for each organic EL 1000 of above-mentioned making, the luminous intensity-current density curve of relation of the corresponding luminous intensity of variation of expression and current density has been shown among Fig. 6.Among the figure, the longitudinal axis is luminous intensity (cd/A), and transverse axis is current density (mA/cm ²).According to this Fig. 6, confirmed in the scope of the current density of measuring that at least the luminous intensity of BPD-A is the highest.

According to above result, the membrance casting condition dependence of hole injection efficiency of having confirmed hole injection layer 4 also works with the situation of single hole element 1000B in organic EL 1000 equally.Namely, confirmed: in the organic EL 1000 of this experiment, when using DC magnetic controlled tube sputtering apparatus, target as tungsten, substrate temperature do not control, the sputter indoor gas by argon gas and oxygen consist of, stagnation pressure is for greater than 2.7Pa and below the 7.0Pa and the ratio of oxygen partial pressure and stagnation pressure is more than 50% and below 70%, the input power density is 1W/cm ²Above and 2.8W/cm ²When coming film forming to consist of the tungsten oxide of hole injection layer 4 by the reactive sputtering method under the following membrance casting condition, the hole injection efficiency from hole injection layer 4 to resilient coating 6A is high, can realize thus excellent low voltage drive and high-luminous-efficiency.

In above-mentioned, the condition for dropping into electric power also represents with the input power density based on table 2.In the situation of using the DC magnetic controlled tube sputtering apparatus different from the DC magnetic controlled tube sputtering apparatus of use in this experiment, drop into electric power and become above-mentioned condition so that drop into power density by correspondingly regulating with the size of target, can similarly obtain with this experiment the hole injection layer 4 that is formed by tungsten oxide of hole injection efficiency excellence.In addition, stagnation pressure, oxygen partial pressure do not rely on the size of device and/or target.

In addition, by reactive sputtering method film forming hole injection layer 4 time, in the sputter equipment under being disposed at room temperature environment, there is not expressly setting substrate temperature.Therefore, before the film forming, substrate temperature is room temperature at least.But in film forming, substrate temperature might rise about tens degree.

The organic EL 1000 of having made hole injection layer 4 under membrance casting condition A is organic ELs 1000 of present embodiment, has near the occupied level of above-mentioned Fermi surface.To this, below will investigate.

(about the electronic state of hole injection layer)

In the tungsten oxide of the hole injection layer 4 of the organic EL 1000 that consists of present embodiment, there is near the occupied level the above-mentioned Fermi surface.Near this Fermi surface occupied level is to form by the membrance casting condition shown in the experiment of adjusting the front.Below be described in detail.

Carried out following experiment: the existence near the occupied level the above-mentioned Fermi surface in the tungsten oxide of film forming under aforesaid membrance casting condition A, B, C is confirmed.

Under each membrance casting condition, made the sample that the photoelectron spectroscopic measurements is used.As the structure of this sample, 1A as shown in Figure 7, on conductivity silicon substrate 70, by above-mentioned reactive sputtering method film forming the tungsten oxide layer 80(of thickness 10nm be equivalent to hole injection layer 4).Below, the sample 1A of membrance casting condition A recorded and narrated be sample A, the sample 1A of membrance casting condition B is recorded and narrated be sample B, the sample 1A of membrance casting condition C is recorded and narrated be sample C.

Sample A, B, C are transferred to and link with this sputter equipment and be filled with in the glove box (glove box) of nitrogen all in sputter equipment after the film forming tungsten oxide layer 80, keep not being exposed to the state of atmosphere.Then, in this glove box, be sealing in the transfer vessel, be installed to the photoelectron light-dividing device.Thus, tungsten oxide layer 80 is not exposed in the atmosphere after film forming and has implemented ultraviolet photoelectron light splitting (UPS) and measured.

At this, usually, UPS spectrum has reflected the state of the occupied level of the valence band etc. of several nanometers from the surface to the degree of depth of measuring object thing.Therefore, in this experiment, observe the state of the occupied level in the top layer of tungsten oxide layer 80 with UPS.

The UPS measuring condition is as follows.In addition, used conductivity silicon substrate 70 in sample A, B, C, (charge up) therefore do not charge in measurement.Measurement point is spaced apart 0.05eV.

Light source: He I ray

Bias voltage: nothing

The angle of emergence: substrate normal direction

The UPS spectrum of the tungsten oxide layer 80 of the A of sample shown in Fig. 8.Transverse axis in conjunction with can initial point be the Fermi surface of substrate 7, with left to as forward.

Below, each occupied level of tungsten oxide layer 80 is described with Fig. 8.

Generally speaking, in the UPS spectrum that tungsten oxide presents, maximum and precipitous rising is well-determined.The tangent line of the flex point by this rising is made as line (i), the intersection point of itself and transverse axis is made as a little (iii).Thus, the UPS spectrum of tungsten oxide is divided into the zone (x) that is positioned at height combination energy side from putting (iii) and the zone (y) that is positioned at low combination energy side (being the Fermi surface side).

At this, according to the ratio of components of the tungsten oxide layer 80 shown in the following table 4, among sample A, B, the C, the ratio of the quantity of tungsten atom and oxygen atom all is roughly 1:3.This ratio of components is obtained by x-ray photoelectron light splitting (XPS).Particularly, use this photoelectron light-dividing device, measure similarly with above-mentioned UPS, tungsten oxide layer 80 is not exposed in the atmosphere and carries out XPS measuring, estimate surface from tungsten oxide layer 80 to the tungsten of several nanometers of the degree of depth and the ratio of components of oxygen.Also put down in writing in the lump the membrance casting condition of tungsten oxide layer 80 in the table 4.

［ table 4 ］

Sample	Sample A	Sample B	Sample C
				Membrance casting condition	Membrance casting condition A	Membrance casting condition B	Membrance casting condition C
Stagnation pressure (Pa)	4.8	2.7	2.7
				Oxygen partial pressure (%)	50	70	70
Drop into electric power (W)	250	500	1000
				Ratio of components (oxygen ÷ tungsten)	3.0	2.9	2.8

According to this ratio of components, can think and in sample A, B, C all be: tungsten oxide layer 80 has in interior scope take tungstic acid as basic atom configuration in several nanometers from the surface to the degree of depth at least, that is to say to have the askew rutile structure (8 bodies have mutually the structure of the oxygen atom on summit) that oxygen atom is combined into 8 body coordinations with respect to tungsten atom as essential structure.Therefore, to be that tungstic acid crystallization or its crystallization are disorder (but do not disconnect in conjunction with (key) in zone among Fig. 8 (x), keeping above-mentioned essential structure) the occupied level based on above-mentioned essential structure that has of noncrystalline, be the zone corresponding with so-called valence band.In addition, the X ray that the present application people has carried out tungsten oxide layer 80 absorbs microstructure (XAFS) measurement, has confirmed all to be formed with in sample A, B, C above-mentioned essential structure.

Therefore, the zone among Fig. 8 (y) corresponding to the band gap between valence band and the conduction band, but shown in this UPS spectrum, sometimes also has as can be known the occupied level different from valence band in this zone of tungsten oxide.The energy level that this is based on other structures different from above-mentioned essential structure is energy level between so-called band gap (in-gap state or gap state).

Then, the UPS spectrum in the zone (y) of each tungsten oxide layer 80 among the A of sample shown in Fig. 9, B, the C.For the intensity of spectrum shown in Figure 9, be arranged in than the point of Fig. 8 (iii) the height about high 3～4eV carried out standardization in conjunction with peak summit value (ii) that can side.In Fig. 9, also (iii) identical transverse axis position showing a little (iii) with the point of Fig. 8.It (iii) is the relative value (relatively in conjunction with energy) of benchmark that transverse axis is expressed as to put, and (Fermi surface side) shows in conjunction with the energy step-down from left to right.

As shown in Figure 9, in the tungsten oxide layer 80 of sample A, from than point (iii) low about 3.6eV in conjunction with can the position to than point (iii) low about 1.8eV in conjunction with can the position till the zone, can confirm to exist the peak.The clear and definite lifting position that (iv) represents in the drawings this peak with point.In sample B, C, can't confirm such peak.

The present invention can bring into play excellent hole injection efficiency by with using as hole injection layer than the tungsten oxide that has the structure of protuberance (being not limited to the peak) in the zone in conjunction with energy about (iii) low 1.8～3.6eV like this in organic EL in UPS spectrum.

At this, the degree that should swell as can be known is more precipitous, and hole injection efficiency is higher.Therefore, as shown in Figure 9, can say than point and (iii) confirm easily that as a comparison this surrectic structure and the more precipitous zone of this protuberance are even more important in the zone in conjunction with energy about low 2.0～3.2eV.

Below, this surrectic structure in the UPS spectrum is called " near the surrectic structure the Fermi surface ".The occupied level corresponding with near the surrectic structure this Fermi surface is above-mentioned " near the occupied level the Fermi surface ".

Then, in order to make near the surrectic structure the above-mentioned Fermi surface clearer and more definite, calculate the differential of the standardization intensity in the UPS spectrum of sample A, B shown in Figure 9, C.

Particularly, use curve is resolved software I GOR Pro6.0, and UPS spectrum shown in Figure 9 is carried out level and smooth (binomial smoothing) (smoothing factor is 1) of binomial 11 times, has then carried out processing based on the differential of central difference method.This is the deviating cause smoothing of the background noise etc. when UPS is measured, and makes differential curve level and smooth, makes following discussion easy to understand.

The differential curve that obtains by this processing has been shown among Figure 10.Point among Figure 10 (iii), (iv) is the transverse axis position identical with Fig. 9.

According to differential curve shown in Figure 10, in the tungsten oxide layer 80 of sample B, C, can be to the zone of point till (iv) (v) from the combination that can measure with the photoelectron light-dividing device, near just up and down fluctuation 0 of differential value, further, (iv) (vi), in conjunction with can side, differential value just roughly increases in the increase of increment rate simultaneously gradually towards high in conjunction with zone that can the about 1.2eV of side to high from point.And (v), (shape of each differential curve of sample B, C vi) is roughly similar to the UPS spectrum as sample B, the C shown in Figure 9 of the primitive curve of this each differential curve in this zone.Therefore, can say that (v), (the UPS spectrum vi) and the shape of its differential curve are the shapes of index function for the zone of sample B, C.

On the other hand, in the tungsten oxide layer 80 of sample A, (iii) see rapid rising from point is (iv) neighbouring to point, (v), (shape of the differential curve vi) is obviously different from the shape of the curve of exponential function in the zone.For such sample A, in the spectrum before the differential of Fig. 9, also can confirm have from point begin near (iv) to swell and also the Fermi surface different from the spectral shape of exponential function near surrectic structure.

In other words, the characteristic of such sample A is, in minimum than the valence band scope in conjunction with hang down about 1.8～3.6eV, there is near the occupied level the Fermi surface, particularly in the combination minimum than valence band can be hanged down the scope of about 2.0～3.2eV, can in UPS spectrum, clearly confirms near the surrectic structure the Fermi surface of correspondence.

Then, for not being exposed to after the film forming in the atmosphere and measured sample A, the B of the UPS spectrum of Fig. 9, the tungsten oxide layer 80 of C, the atmosphere that has carried out at normal temperatures a hour exposes to the open air.Then, re-start UPS and measure, the variation of the spectrum that causes is thus confirmed.UPS spectrum in the above-mentioned zone shown in Figure 11 (y).Follow the example of and Fig. 9 of transverse axis are same, and the point among the figure (iii), (iv) is the transverse axis position identical with Fig. 9.

According to UPS spectrum shown in Figure 11, in the tungsten oxide layer 80 of sample B, C, similarly there is not near the surrectic structure the Fermi surface before exposing to the open air with atmosphere.With respect to this, in the tungsten oxide layer 80 of sample A, although atmosphere exposes rear intensity to the open air and/or spectral shape can be found out variation, still can confirm near the surrectic structure that exists Fermi surface.Hence one can see that, for sample A, exposes to the open air even carry out the atmosphere of certain hour, also can keep atmosphere and expose front characteristic to the open air, has certain stability with respect to the surrounding enviroment atmosphere.

Above, the UPS spectrum of measuring for sample A, B, C is discussed, but in XPS or hard X ray photoelectron spectroscopic measurements, also can similarly be confirmed near the above-mentioned Fermi surface surrectic structure.

Figure 12 is the XPS spectrum after the above-mentioned atmosphere of the tungsten oxide layer 80 of sample A exposes to the open air.In order to compare the overlapping UPS spectrum (identical with Fig. 8) of having described the tungsten oxide layer 80 of sample A.

In the XPS measuring condition, except light source is Al K alpha ray, be same with aforesaid UPS measuring condition.In Figure 12, the point among the figure (iii) is the transverse axis position identical with Fig. 8, and transverse axis similarly (iii) can represent for the relative combination of benchmark in order to point with Fig. 9.In addition, among Figure 12 with (i) ' line suitable with Fig. 8 (i) in the expression XPS spectrum.

As shown in figure 12, in XPS spectrum, also with the situation of UPS spectrum similarly, can hang down in the scope of about 1.8～3.6eV in the combination minimum than valence band, as the surrectic structure of suitable size, can confirm clearly near the surrectic structure that in the tungsten oxide layer 80 of sample A, exists the Fermi surface.By other experiments, in the light splitting of hard X ray photoelectron, can confirm too near the surrectic structure the Fermi surface.

In above-mentioned measurement, as the sample that the photoelectron spectroscopic measurements is used, used different from the structure of organic EL shown in Figure 1 1000, form sample 1A(Fig. 7 that tungsten oxide layer 80 form at conductivity silicon substrate 70).The measure that this just is used for preventing the charging of measuring not is that the structure with organic EL of the present invention is defined as this structure.

Other experiments of carrying out according to the present application people, use has the sample of the structure (being formed with successively the anode 2 that formed by ITO and the structure of the hole injection layer 4 that formed by tungsten oxide in the one side of substrate 1) of organic EL shown in Figure 1 1000, in the situation that carried out UPS, XPS measuring, charging has occured in the measurement.

But, when and with eliminate charging in and during rifle, although each occupied level of hole injection layer 4 present in conjunction with can absolute value (for example value in conjunction with energy during as initial point with the Fermi surface of photoelectron light-dividing device itself) tungsten oxide layer 80 from sample 1A is different sometimes, but at least from the band gap to the valence band minimum in conjunction with can scope in, can obtain the spectrum with the same shape of sample 1A.

(about the investigation of hole injection efficiency)

In the hole injection layer that is formed by tungsten oxide, can think according to UPS spectrum etc.: the principle that near the occupied level the Fermi surface that can be confirmed as near the surrectic structure the Fermi surface works to hole injection efficiency is as described below.

Near the film of tungsten oxide, above-mentioned Fermi surface that crystallization can be seen occupied level because of oxygen defect and/or its similarly structure produces, this point has a large amount of reports according to the result of experiment and First Principle calculating.

Particularly, be speculated as because producing in conjunction with track and/or 5d track, described in conjunction with track be for want of oxygen atom and the adjacent tungsten atom that forms the 5d track each other in conjunction with track, described 5d track is the 5d track that is not present in the tungsten atom monomer in film surface and/or the film by the oxygen atom end-blocking.Infer: when these 5d tracks are partly to account for or non-when accounting for state, then when contact with organic molecule, for mutual energy stabilization, can be from the highest occupied orbital extraction electronics of organic molecule.

In fact, there is report to point out: at tungsten oxide with have in the molybdenum oxide of catalytic action and/or electrochromism, a plurality of common physical property such as photochromic, during stacked α-NPD by organic low molecular forms on its film layer, electronics moves (with reference to non-patent literature 2) from α-NPD molecule to Electrochromic Molybdenum Oxide Coatings.

The present application people thinks, with the 5d track of adjacent tungsten atom comparing in conjunction with track each other, in the tungsten oxide in conjunction with tungsten atom monomer that can be lower partly account for the 5d track or with its similarly structure be equivalent near the Fermi surface occupied level.

Figure 13 is the energy diagram at the interface of the tungsten oxide layer with near the occupied level the Fermi surface of the present invention and α-NPD layer.

Among Figure 13, the minimum combination of valence band that at first shows in this tungsten oxide layer (being equivalent to hole injection layer) can (be designated as " valence band upper end ") and near the combination energy of the lifting position of the occupied level that Fermi surface is (be designated as " in-gap state upper end " among the figure) among the figure.In UPS spectrum, be equivalent to the point of Fig. 8 on the valence band (iii), be equivalent to the point of Fig. 9 on the in-gap state (iv).

And, show also that stacked α-NPD(is equivalent to functional layer on this tungsten oxide layer) time the thickness of α-NPD layer and the highest occupied orbital of α-NPD in conjunction with can and the relation of vacuum level.At this, the combination of high occupied orbital of α-NPD can refer in the UPS spectrum this peak of high occupied orbital lifting position in conjunction with energy.

Particularly, this tungsten oxide layer for film forming on ito substrate, on one side the photoelectron light-dividing device and and the ultra high vacuum evaporation coating device that links of this device between substrate is come and gone, Yi Bian repeatedly carry out the ultra high vacuum evaporation of UPS measurement and α-NPD, thereby obtain the energy diagram of Figure 13.Owing in UPS measures, not confirming charging, therefore in Figure 13, the combination of the longitudinal axis can be labeled as the absolute value take the Fermi surface of ito substrate as initial point.

As can be seen from Figure 13, thickness at α-NPD layer is in the scope of at least 0～0.3nm, that is to say the near interface at this tungsten oxide layer and α-NPD layer, the combination of the highest occupied orbital of the in-gap state of this tungsten oxide layer upper end and α-NPD can about equally, can be said to be mutual energy level continuum of states (following it is called " interface energy level is continuous ").In fact comprise the poor of a little in this said " equating ", particularly refer to ± 0.3eV is with interior scope.

Further, to show above-mentioned interface energy level be not that interaction accidental but by tungsten oxide and α-NPD realizes to Figure 13 continuously.

For example, the variation of the vacuum level in the interface (vacuum level displacement) illustrate according to its change direction interface formation have take the tungsten oxide layer side as negative, take α-NPD layer side as positive electric double layer.In addition, because the size of its vacuum level displacement is very large, near 2eV, so what think that electric double layer is that effect owing to similar chemical bond (chemical bond) forms is appropriate.That is, above-mentioned interface energy level should think that continuously interaction by tungsten oxide and α-NPD realizes.

The present application people infers as concrete interaction and following mechanism.

At first, near the occupied level the Fermi surface is that 5d track by tungsten atom produces as mentioned above.Below, be referred to as " the W5d track of surrectic structure ".

On the surface of this tungsten oxide layer, when the highest occupied orbital of α-NPD molecule during near the W5d track of surrectic structure, for mutual energy stabilization, the W5d rail moving of electronics from the highest occupied orbital of α-NPD molecule to surrectic structure.Thus, at the interface formation electric double layer, cause that vacuum level displacement, interface energy level are continuous.

Further, particularly, the nitrogen-atoms of the probability density deflection amine structure of the highest occupied orbital of α-NPD molecule and distributing, and constitute lone pair take this nitrogen-atoms as principal component, the existing a large amount of report of result that this calculates as First Principle.Accordingly, infer: this tungsten oxide layer and amine be molecule organic layer at the interface, the W5d rail moving of electronics from the lone pair of the nitrogen-atoms of amine structure to surrectic structure.

As the report of supporting above-mentioned supposition, following report is arranged: as previously mentioned have with the vapor-deposited film of the molybdenum oxide of the common physical property of tungsten oxide with as amine be organic molecule NPB, α-NPD, F8BT each at the interface, exist and the continuous same interface energy level continuously (with reference to non-patent literature 3,4,5) of the interface energy level of tungsten oxide layer shown in Figure 13 and α-NPD layer.

The hole injection efficiency of the excellence that the hole injection layer of organic EL of the present invention has can be described continuously according to above interface energy level.Namely, it is continuous between the hole injection layer that is formed by the tungsten oxide with near the occupied level the Fermi surface and adjacent functional layer interface energy level to occur, near the lifting position of the occupied level the Fermi surface in conjunction with can and the combination of the highest occupied orbital of functional layer can be about equally.Between its continuous energy level, cause the hole injection.Hole injection barrier during therefore, to the highest occupied orbital injected hole of functional layer is no better than zero.

But, be difficult to think fully not as the oxygen defect of the main cause that forms near the occupied level the Fermi surface and/or its similarly the such material of tungsten oxide of structure be in esse.For example, although yet think in aforesaid sample B, C etc., photoelectron spectrophotometric spectra, do not have oxygen defect near the tungsten oxide of the surrectic structure the Fermi surface and/or its similarly structure be still existing of minute quantity, this is appropriate.

To this, single hole element HOD-A of the hole injection layer 4 that has like that the tungsten oxide layer 80 that is equivalent to sample A shown in the experiment of front and the reason that organic EL BPD-A presents excellent hole injection efficiency are described with Figure 14.

When the stacked functional layer of tungsten oxide layer, the highest occupied orbital of the organic molecule that consists of functional layer and near the occupied level of Fermi surface of tungsten oxide layer are interacted, at the interface, (for example amine is the nitrogen-atoms of the amine structure in the organic molecule to need in the organic molecule the high position of probability density of the highest occupied orbital.Represent with " injection phase (y) " among the figure) and the oxygen defect of tungsten oxide layer and/or its similarly structure (representing with " injection phase (x) " among the figure) near (contact) interactional distance extremely.

But, shown in Figure 14 (b), even have injection phase (x) in tungsten oxide layer aforesaid sample B, C etc., that do not have near the surrectic structure the Fermi surface, its number density is also little as not reach the degree that presents near the surrectic structure the Fermi surface in UPS spectrum.Therefore, injection phase (y) is very low with the possibility that injection phase (x) contacts.Because (x) contacts with injection phase (y) in the injection phase local injected hole, so the hole injection efficiency extreme difference of sample B, C as can be known.

With respect to this, shown in Figure 14 (a), in the tungsten oxide layer with near the surrectic structure the Fermi surface of aforesaid sample A etc., there is abundant injection phase (y).Therefore injection phase (y) is high with the possibility that injection phase (x) contacts as can be known, and hole injection efficiency is high.

The above is summarized, as described belowly illustrate that organic EL of the present invention has excellent hole injection efficiency.

At first, the hole injection layer that is formed by tungsten oxide has near the surrectic structure the Fermi surface in its photoelectron spectrophotometric spectra.This means and have many oxygen defects and/or its similar structure on its surface.

And near the occupied level itself the Fermi surface is captured electronics from the organic molecule that consists of adjacent functional layer, has thus with the highest occupied orbital of organic molecule to realize the effect that interface energy level is continuous.

Therefore, when the surface at hole injection layer has many oxygen defects and/or its similar structure, the contacted probability in position that then probability density of the highest occupied orbital of near the occupied level the Fermi surface and organic molecule is high is high, can effectively produce the interface energy level continuous action, present excellent hole injection efficiency.

(film about hole injection layer reduces)

The present application people except above-mentioned evaluation device (having omitted the structure of dike 5), has also made organic EL 1000(Fig. 1 of new interpolation dike 5 in order to confirm to form through dike the characteristic of the organic EL of operation) test.Its result has confirmed that as above commentary valency device carries out low voltage drive like that, the characteristics of luminescence is improved well.

At this, the present application people confirms the organic EL of made, found that: compare attenuation (below, be designated as " film minimizing ") behind the thickness of hole injection layer and this layer of firm formation.At this, the film that the present application people is speculated as this hole injection layer reduces owing to dike formation operation occurs.So, for the film of finding out hole injection layer reduces phenomenon, also carried out following affirmation experiment.

As concrete method, at first on glass substrate by sputtering film-forming by the tungsten oxide that becomes hole injection layer consist of the layer (membrance casting condition is the condition identical with single hole element).Then, on this hole injection layer, based on the resin material layer that spin-coating method stacked (room temperature, 2500rpm/25sec) is made of predetermined resin material (Tokyo Applied Chemistry Industrial Co., Ltd.'s system " TFR " series), then make through baking and banking up with earth processing (100 ℃, 90sec).Then, development treatment (using TMAH2.38% solution, developing time 60sec) and clean (using pure water, scavenging period 60sec) have been carried out.Then, peel off resin material layer.Set and development treatment, the clean of this resin material layer is that the actual dike of imagination forms operation and definite.

This experiment condition and result are illustrated in the table 5.In addition, the film density in the expression table 5 shown in Figure 15 and film reduce the coordinate diagram of the relationship between quantities.

［ table 5 ］

Sample	Sample A	Sample B	Sample C
				Stagnation pressure (Pa)	4.8	2.7	2.7
Ar：O 2	100：100	43：100	43：100
				Drop into electric power (W)	250	500	1000
Film density (g/cm 3）	5.43	6.09	6.33
				Film reduction (nm)	57.7	25	20.9
Appendix/film formation device	SMD	SOLCIET	SOLCIET

Shown in the experimental result of table 5, as the tungsten oxide layer of hole injection layer after with respect to firm film forming thickness (80nm) and finally become thickness about 23nm.Thus, confirm in fact owing to the film minimizing reaches the approximately tungsten oxide layer disappearance (with reference to the best sample A of characteristic) of the thickness amount about 57nm.

In addition, as shown in figure 15, have suitable causality between the film reduction of tungsten oxide layer and the film density, film density is lower as can be known, the film reduction is larger.

Although this reason is current also indefinite, according to table 4,5 and the coordinate diagram of Figure 15 as can be known, the membrane properties such as the characteristics of luminescence of tungsten oxide layer are better, film density is lower.The research of other that are undertaken by the present application people can be speculated as: tungsten oxide layer can obtain good hole injection, so can realize the low voltage drive of element owing to having the structure film density that causes because of the oxygen shortcoming reduce in layer.

In addition, the film that the present application people has investigated tungsten oxide layer reduces reason, and the result has distinguished: because the film minimizing has occured so that tungsten oxide layer is dissolved the solvent that uses in development treatment or clean.When tungsten oxide layer had the structure that forms because of the oxygen shortcoming, then film density reduced as mentioned above, was formed with a large amount of small crystal structures in layer but this also is considered to.Think: owing to being formed with a large amount of small crystal structures like this, so that employed solvent (developer solution, cleaning fluid etc.) easily is immersed in the tungsten oxide layer in the film-forming process when forming dike, therefore film occurs reduce.

Usually, when aforesaid film occuring reduce, then be difficult to manage the thickness of tungsten oxide layer, in addition, the hole injection properties after also worrying element finished makes any difference.Therefore, known hypothesis those skilled in the art in the situation of the generation that the film of such hole injection layer reduces, whether estimation can hesitate uses tungsten oxide to consist of hole injection layer.

Yet, the present application people has just carried out wholwe-hearted research for this point, found that: bake and bank up with earth condition by for example suitably changing development conditions (solution level is reduced to about 0.2% from 2.38%) or suitably changing, can regulate the film reduction of tungsten oxide layer.Thus, can realize considering the film thickness monitoring of the tungsten oxide layer that film reduces.So the technology that the present application people relates to take the adjusting of the film reduction of this hole injection layer is as basis, further the trial-production of the light-emitting component of reality is studied, confirmed following technology item.

As the trial-production step of light-emitting component, at first form the hole injection layer that comprises tungsten oxide at anode.Then stacked dike material layer on this hole injection layer, forms the dike material layer pattern reservation shape (implementing to expose, develop, clean each this moment processes) of the peristome with the functional layer of being used to form.Then, at the position film forming function layer corresponding with described peristome.Form negative electrode in functional layer.

Structure to the element that obtains by the method is confirmed, has confirmed: in the zone corresponding with described peristome of hole injection layer, form the depression that the tungsten oxide dissolving forms, hole injection layer constitutes and having as a whole the depression structure thus.

At this, obtained following opinion: when having formed the recess configuration of hole injection layer, then in the situation that drive light-emitting component, the electric field that produces between anode and negative electrode can be concentrated the edge part that puts in place in the depression structure of the end side of described peristome, might cause luminance nonuniformity, life-span in the illuminating part face low inferior, might cause damaging the characteristics of luminescence.

So the present application people is contemplated that shown in following execution mode the shape by dike prevents the bad structure of concentrating at the edge generation electric field of such depression structure.

Then, by with execution mode 1 difference centered by other execution modes of the present invention are described.

＜execution mode 2 〉

(overall structure of OLED display)

Figure 17 is the vertical view of the part of the OLED display that relates to of expression embodiment of the present invention 2.

OLED display 100 is equivalent to the organic EL 1000 of execution mode 1 for organic EL 10a, 10b, the 10c(that is rectangular configuration and possesses arbitrary luminescent layer of RGB) OLED display of the top emission structure that forms.Each organic EL is brought into play function as sub-pixel, and the organic EL of one group of RGB three look is brought into play function as pixel.

In the example of Figure 17, adopted the pixel dike 55 of well word shape, to carrying out zoning at X-direction adjacent luminescent layer 56a1,56b1,56c1, and luminescent layer 56a2,56b2,56c2 are carried out zoning by the dyke part 55a that extends in Y direction.

On the other hand,, luminescent layer 56b1,56b2 are carried out zoning, and luminescent layer 56c1,56c2 are carried out zoning carrying out zoning at Y direction adjacent luminescent layer 56a1,56a2 by the dyke part 55b that extends at directions X.

Figure 18 is the cutaway view that schematically illustrates a part of section of the OLED display that embodiment of the present invention relates to, and shows the A-A section of Figure 17.Figure 19 is the amplification view of the B section that is surrounded by single-point line among Figure 18.

As with the difference of the element 1000 of execution mode 1, on anode 2, be equipped with hole injection layer 4 across ITO layer 3.In addition, omit resilient coating 6A, be equipped with electron injecting layer 7 at luminescent layer 6B, be equipped with envelope at negative electrode 8 and end layer 9.

On substrate 1, be the rectangular anode 2 that is formed with, on anode 2, be laminated with in the following order the ITO(tin indium oxide) layer 3 and hole injection layer 4.In addition, only be layered on the anode 2 with respect to ITO layer 3, hole injection layer 4 not only is formed on the anode 2, also is formed on above substrate 1 whole.

ITO layer 3 has the good function of zygosity that makes each interlayer between anode 2 and hole injection layer 4.

Peripheral upper portion at anode 2 is formed with dike 5 across hole injection layer 4, in the regional inner stacks by dike 5 regulations luminescent layer 6B is arranged.And then on luminescent layer 6B, electron injecting layer 7, negative electrode 8 and envelope are ended layer 9 and are formed and cross respectively by the zone of dike 5 regulations that to end layer 9 continuous separately with electron injecting layer 7, negative electrode 8 and the envelope of adjacent organic EL 10a, 10b, 10c.

Electron injecting layer 7 has the function of carrying from negative electrode 8 injected electrons to luminescent layer 6B, and for example, preferably the combination by barium, phthalocyanine, lithium fluoride or these materials forms.

Negative electrode 8 is monolayer constructions will at this, such as by ITO, IZO(indium zinc oxide) etc. form.In the situation of the light-emitting component of top emission structure, preferably the material by transmitance forms.

Envelope is ended layer 9 and is had and can suppress luminescent layer 6B etc. and be exposed in the moisture or be exposed to airborne function, such as by the SiN(silicon nitride), the SiON(silicon oxynitride) etc. material form.In the situation of the light-emitting component of top emission structure, preferably the material by transmitance forms.

(about hole injection layer)

Hole injection layer 4 is same with hole injection layer in the execution mode 1, is made of tungsten oxide (WOx) layer of the membrance casting condition film forming by can obtaining good hole injection properties.At this, as shown in figure 19, hole injection layer 4 extends out to the side along bottom surface 5a, the 5b of dike 5, and a top part caves in and formation recess 4a.Bottom surface 4b as the inner bottom surface section of recess 4a is lower than the horizontal plane 5c of dike bottom surface 5a.Recess 4a is made of bottom surface 4b and the inboard facial side 4d of conduct continuous with it, and the degree of depth of recess 4a is roughly about 5nm～30nm.The edge 4c of recess is the salient angle part that the side 4d by the top regional 4e that does not cave in of hole injection layer 4 and recess forms, and the 5d of covering section that is used as the part of dike 5 covers.

Because the edge 4c of recess is outstanding with respect to the bottom surface 4b of recess, so as the edge 4c of hypothesis recess when the 5d of covering section of being insulated property covers, can occur herein then that electric field is concentrated and at luminescent layer 6B local flow electric current, its result, the problem that can produce the luminance nonuniformity in the light-emitting area and/or be shortened by the local deteriorated life of product that causes of luminescent layer 6B.But, in the present embodiment, because the 5d of covering section of edge the being insulated property of 4c of recess covers, so can suppress the generation of such problem.In addition, concentrate in order effectively to suppress electric field, preferably make the thickness (beeline from the edge 4c of recess to luminescent layer 6B) of the 5d of covering section be 2nm～5nm.

In addition, and as an example and seamed edge as shown in figure 19 (edge) shape that illustrates is compared, the edge 4c by making recess is shaped as polygon or with the shape of fillet, can further suppresses electric field and concentrate.

In addition, in the present embodiment, the 5d of covering section arrives the bottom surface 4b of recess 4a, and the side of dike 5 is up inclined-plane from the point of arrival that arrives recess bottom surface 4b to the limit.Thus, in the situation that form luminescent layer 6B by printing technologies such as ink-jet methods, can make China ink be easy to enter corner by in the zone of dike regulation, can suppress the generation in space etc.

The process of a kind of mode that＜acquisition the present invention relates to 〉

At this, use accompanying drawing to specify the content of record in above-mentioned " film of hole injection layer reduces ".

Figure 16 is the cutaway view of the manufacturing process of expression OLED display.(a) of Figure 16 shows the state that is formed with anode 2, ITO layer 3, hole injection layer 4 and dike 5 at TFT substrate 1.In addition, Figure 16 (b) further shows the state that luminescent layer 6B, electron injecting layer 7, negative electrode 8 and envelope are ended layer 9 that is formed with.

According to the structure of having used tungsten oxide in charge injection transfer layer (being hole injection layer 4 in this example), in the forming process of dike 5, formation recess 4a(is with reference to Figure 16 (a) on hole injection layer 4).In the situation that formed luminescent layer 6B (with reference to (b) of Figure 16) under this state, electric field can focus near the edge 4c of recess when luminous.Its result, sometimes at luminescent layer 6B local flow electric current owing to producing this local electric current, probably can produce in the light-emitting area luminance nonuniformity and/or by the problem of the deteriorated lifetime that causes in part.

Above-mentioned problem and opinion be used in the organic EL of tungsten oxide distinctive, and, think it up to the present is unclear always, this is the meaning on possessing skills.

As mentioned above, by a series of research and discussion, the inventor has expected following technical characterictic: the edge that covers the recess of the charge injection transfer layer formation that comprises tungsten oxide by the part with dike, charge concentration is near the edge of recess when suppressing luminous, its result suppresses local flow electric current in the luminescent layer.

The manufacture method of＜OLED display 〉

Figure 20～Figure 22 is the process chart of the manufacture method of the OLED display that relates to of explanation embodiment of the present invention.

At first, shown in Figure 20 (a), form the Ag film at substrate 1 by for example sputtering method, by for example photoetching process this Ag Thinfilm pattern is rectangular formation anode 2 thus.In addition, the Ag film also can form by vacuum vapour deposition etc.

Next, shown in Figure 20 (b), form ito thin film by for example sputtering method, by for example photoetching process this ito thin film patterning is formed ITO layer 3 thus.Then, form the film 11 of WOx or MoxWyOz by technology such as vacuum evaporation, sputters with the constituent that comprises WOx or MoxWyOz.

Next, shown in Figure 20 (c), form dike material layers 12 at film 11, remove the part of dike material layer 12 and the part of film 11 is exposed.For the formation of dike material layer 12, can by such as the coating etc. form.For removing of dike material layer 12, can be by forming the resist patterns at dike material layer 12, then it being carried out etching and remove.The resist pattern is removed by the remover of for example water system or non-water system after etching.

Next, use pure water to clean etch residue.At this moment, owing to having the character that easily is dissolved in pure water as WOx or the MoxWyOz of the material that consists of film 11, so as Figure 21 (a) shown in, the exposed portions serve of film 11 is etched and forms depression and construct.Its result forms the hole injection layer 4 that possesses recess 4a.

Next, shown in Figure 21 (b), implement heat treatment, give to a certain degree flowability to the residual section of dike material layer 12, make the dike material extend to the edge 4c of recess from residual section.Thus, the edge 4c coating cap 5d of recess covers.Heat treatment for example can adopt hot blast to process (heat cure).For temperature and the time that hot blast is processed, the thickness of the kind of consideration dike material and/or the required 5d of covering section etc. is suitably set and is got final product.Then, as required, residual surperficial embodiment of dike material layer 12 processed such as the liquid of dialling that is undertaken by fluoro plasma etc., form dike 5.

Next, shown in Figure 21 (c), in by the zone of dike 5 regulation, by for example ink-jet method constituent China ink that comprises organic EL Material (below referred to as " China ink ") that drips, make the dry and formation luminescent layer 6B of this China ink.In addition, also can be by China inks that drips such as a minute method of the use of ink and water, nozzle coating (nozzle coat) method, spin-coating method, intaglio printing, letterpress.

Next, shown in Figure 22 (a), become the titanate thin film of electron injecting layer 7 by for example vacuum vapour deposition, shown in Figure 22 (b), form the ito thin film that becomes negative electrode 8 by for example sputter, shown in Figure 22 (c), further form envelope and end layer 9.

According to above-mentioned manufacture method, even the exposed portions serve at hole injection layer 4 has formed recess 4a in manufacture process, because the edge 4c coating cap 5d of recess covers, then form luminescent layer 6B, so also can suppress the edge 4c that electric field focuses on recess.

Abovely be illustrated based on execution mode, but the invention is not restricted to these execution modes.For example can consider following variation.

(1) in the above-described embodiment, as the material that consists of hole injection layer 4, use WOx or MoxWyOz to be illustrated, but generally speaking, because metal oxide, metal nitride, metal oxynitride are easily corroded by pure water, so using the Mo(molybdenum), W(tungsten) in addition the situation of metal, also can play same effect by using present embodiment.

(2) in the above-described embodiment, hole injection layer is corroded by pure water when cleaning and has formed recess, but when employing was of the present invention, even formed recess by reason in addition, the electric field that also can be inhibited focused on the effect at the edge of recess.Reason in addition for example can list: the hole injection layer situation that etched liquid corrodes when etching; When peeling off, resist is stripped from the situation of agent erosion etc.Like this, in the situation that in the situation that the material of employed corroded by liquid consists of when hole injection layer is formed dike by meeting, more specifically can be consisted of by the material of employed corroded by liquid under by the state that exposes in the part of hole injection layer, the present invention is effective.

(3) in the above-described embodiment, surpass the edge 4c of recess and arrive the bottom surface 4b of recess from covering section that dike extends out, but the present invention then is not limited to said structure so long as cover the edge 4c of recess.For example, as shown in figure 23, can not arrive for the 5d of covering section the bottom surface 4b of recess yet.In the situation of the structure that has adopted Figure 23, because can make the dike material not flow to the recess bottom surface, it is low temperature and short time so can make heat treated temperature and time.

In the above-described embodiment, as an example of the method for the recess 4a that forms hole injection layer 4, show the development that is formed in the operation by dike and clean to form, but the present invention also can use mask patterning etc. as other formation method.

(4) in (a) of Figure 21, the lower end on the inclined-plane of dike material 12 is consistent with the edge 4c of recess, but is not limited to that it can't be otherwise.Sometimes also shown in Figure 24 (a), according to the dike material, the inclined-plane by dike material 12 retreats, and the part of the regional 4e that does not cave in is exposed.In this case, the edge 4c that also covers recess by dike material 12 is suitably implemented heat treatment by the part of dike material gets final product (with reference to (b) of Figure 24).

(5) in the above-described embodiment, as the charge injection transfer layer, only hole injection layer 4 is inserted between anode and the luminescent layer, but the invention is not restricted to this.For example, as shown in figure 25, also can form hole transporting layer 13 at hole injection layer 4, they are inserted between anode and the luminescent layer as the charge injection transfer layer.In this case, formation recess on hole transporting layer 13 is covered the edge of the recess be formed at hole transporting layer by covering section.

Further, also can the charge injection transfer layer only be consisted of the hole transporting layer that between anode and luminescent layer, accompanies this hole injection layer and consist of functional layer by hole injection layer.Particularly, shown in the part B of Figure 27, under the state that also can be covered by the 5d of covering section of dike 5 at the edge 4c of the recess 4a of hole injection layer 4, comprise the China ink of hole transporting material and form hole transporting layer 13 in the recess 4a of hole injection layer 4 coating, comprise the China ink of luminescent material and form luminescent layer 6 in these hole transporting layer 13 coatings.

In addition, hole transporting layer is the layer about thickness 10nm～20nm, has the function of will carry in from the hole injection layer injected holes to organic luminous layer.Use the organic material of cavity conveying as hole transporting layer.The organic material of cavity conveying is to have the organic substance that transmits the character in the positive hole that generates by intermolecular electric charge mobile response.This material is also sometimes referred to as p-type organic semiconductor.

Hole transporting layer can be that macromolecular material also can be low molecular material, comes film forming by the wet printing method.When preferably being contained in the organic luminous layer that forms as the upper strata so that this hole transporting layer is not easy stripping (wash-out) to the crosslinking agent of organic luminous layer.As the example of the material of positive hole transporting, can use to comprise fluorenes position and the copolymer at triallylamine (triallylamine) position, low-molecular-weight triallylamine derivative.As the example of crosslinking agent, can use dipentaerythritol acrylate (dipentaerythritol hexaacrylate) etc.In this case, preferably by poly-(3,4-rthylene dioxythiophene) of the polystyrolsulfon acid that mixed (PEDOT-PSS) and/or its derivative (copolymer etc.) form.

(6) in the above-described embodiment, form anode 2 by the Ag film, therefore formed ITO layer 3 thereon.When anode 2 was the aluminium based material, can cancel ITO layer 3 and make anode was monolayer constructions will.

(7) in the above-described embodiment, as the light-emitting device that possesses a plurality of light-emitting components, be illustrated as an example of OLED display example, but the invention is not restricted to this, also go for lighting device etc.

(8) in the above-described embodiment, adopt so-called pixel dike (groined type shape dike), but the invention is not restricted to this.For example, can adopt line dike (dike of wire).In the example of Figure 26, adopted line dike 65, luminescent layer 66a, 66b, 66c adjacent on X-direction are divided.In addition, as shown in figure 26, in the situation that adopt line dike 65, although adjacent luminescent layer is not stipulated by the dyke part each other on Y direction, but by suitably setting driving method, anode dimension and interval etc., can make it to be independent of each other mutually and carry out luminous.

(9) in the above-described embodiment, being illustrated with top emission structure, but being not limited to this, also can be bottom emissive type.

(10) in the above-described embodiment, between luminescent layer and negative electrode, only inserted electron injecting layer, but also can insert electron supplying layer in addition.

(11) in the upper execution mode, used organic material as the dike material, but also can use inorganic material.

In this case, with the situation of using organic material similarly, such as forming the dike material layer by coating etc.Can form the resist pattern at the dike material layer, use afterwards predetermined etching solution (Tetramethylammonium hydroxide (TMAH) solution etc.) to carry out etching, remove thus the dike material layer.The resist pattern is for example removed by the remover of water system or non-water system after etching.Then, clean etch residue with pure water.At this moment, have the character that easily is dissolved in pure water, TMAH solution as WOx or the MoxWyOz of the material that consists of film, therefore with the situation shown in (a) of Figure 21 similarly, the exposed portions serve of film is etched and forms the depression structure.Its result forms the hole injection layer that possesses recess.Therefore, in the situation that as dike materials'use inorganic material, also can similarly use the present invention with the situation of using organic material.

(other business)

" occupied level " that mentions in this specification refers to the electron energy level by the electron orbit of at least 1 electrons occupy, includes the so-called energy level that partly accounts for track.

Organic EL of the present invention is not limited to the structure that element uses separately.Also can be by a plurality of organic ELs be integrated on the substrate as pixel, thus consist of organic EL panel.Such OLED display can be implemented by the thickness of suitably setting each layer in each element.

Utilizability on the industry

Organic EL of the present invention can be used in the display element of the employed display of mobile phone, television set etc., various light sources etc.In any purposes, can both use as the organic EL that in the large luminance range of the high briliancy from low briliancy to the light source purposes etc., carries out low voltage drive.According to such high-performance, the various display unit, TV set device, portable electric appts that can be widely used as home-use or communal facility or professional usefulness are with display, lighting source etc.

Claims (18)

1. organic EL possesses:

Anode;

Negative electrode;

Functional layer, it is configured between described anode and the described negative electrode, by comprising that 1 layer of using luminescent layer that organic material forms or multilayer consist of;

Hole injection layer, it is configured between described anode and the described functional layer; With

Stipulate the dike of described luminescent layer,

Described hole injection layer comprises tungsten oxide, can have occupied level in the zone at minimum than valence band in conjunction with the combination that can hang down 1.8～3.6eV,

Described hole injection layer forms the part on the surface of described functional layer side and compares the depression structure that more is positioned at described anode one side with other parts in the zone by described dike regulation,

The edge of the recess in the described depression structure is covered by the part of described dike.

2. organic EL according to claim 1,

Because there is described occupied level, at the stacked interface of described hole injection layer and described functional layer, the combination of the highest occupied orbital of described functional layer can be positioned in described occupied level in conjunction with can near.

3. organic EL according to claim 1,

At the stacked interface of described hole injection layer and described functional layer, the combination of described occupied level can with the highest occupied orbital of described functional layer in conjunction with can difference in ± 0.3eV.

4. the described organic EL of any one according to claim 1～3,

In UPS spectrum, described hole injection layer is the bossed shape of tool in the combination energy in conjunction with can hang down 1.8～3.6eV minimum than valence band is regional.

5. the described organic EL of any one according to claim 1～4,

In XPS spectrum, described hole injection layer is the bossed shape of tool in the combination energy in conjunction with can hang down 1.8～3.6eV minimum than valence band is regional.

6. the described organic EL of any one according to claim 1～5,

In the differential smoothing of UPS spectrum, described hole injection layer have the shape that shows as the function different from exponential function in the whole combination energy zone in conjunction with hanging down 2.0～3.2eV minimum than valence band.

7. the described organic EL of any one according to claim 1～6,

Described functional layer comprises the amine based material.

8. the described organic EL of any one according to claim 1～7,

Described functional layer is to carry the hole transporting layer in hole and be used for the adjustment optical characteristics or at least either party of the resilient coating of the purposes of obstruction electronics.

9. the described organic EL of any one according to claim 1～8,

The described occupied level of described hole injection layer is present in the combination minimum than valence band and can hangs down in the combination energy zone of 2.0～3.2eV.

10. organic EL according to claim 1,

The part of described dike reaches the recess bottom surface of the depression structure of described hole injection layer, and the side of described dike is up inclined-plane to the limit from the point of arrival that arrives described recess bottom surface.

11. organic EL according to claim 1,

The part of described dike does not arrive the recess bottom surface of the depression structure of described hole injection layer.

12. organic EL according to claim 1,

Described hole injection layer extends to the side of described dike along the bottom surface of described dike.

13. organic EL according to claim 1,

The salient angle part that the edge of the described recess of described hole injection layer forms for the side by the top zone of not caving in of described hole injection layer and described recess.

14. organic EL according to claim 1,

Described dike has liquid repellency, and described hole injection layer has lyophily.

15. a display unit possesses the described organic EL of any one in the claim 1～14.

16. the manufacture method of an organic EL comprises:

The 1st operation is prepared anode;

The 2nd operation, to described anode film forming tungsten oxide layer, to be used as the gas in the sputtering chamber of sputter equipment by the gas that argon gas and oxygen consist of, the stagnation pressure of described gas for greater than 2.7Pa and below the 7.0Pa, the ratio of oxygen partial pressure and stagnation pressure is more than 50% and below 70% and the input power density of target per unit area is 1W/cm ²Above and 2.8W/cm ²The described tungsten oxide layer of film forming under the following membrance casting condition;

The 3rd operation forms the dike material layer that is formed by the material that consists of dike in described tungsten oxide layer;

The 4th operation, remove the part of described dike material layer, the part of described tungsten oxide layer is exposed, the top part of described tungsten oxide layer is compared with other top parts more be positioned at described anode one side, form have inner bottom surface and with the depressed part of the continuous medial surface of described inner bottom surface;

The 5th operation by implementing heat treatment to residual of the described dike material layer on the described tungsten oxide layer, is given flowability to the residual section of described dike material layer, makes the material that consists of described dike extend to the edge of the recess of described depressed part from described residual section;

The 6th operation after described heat treatment step, forms the functional layer that comprises luminescent layer in the described tungsten oxide layer of exposing; And

The 7th operation forms negative electrode above described functional layer.

17. the manufacture method of organic EL according to claim 16,

In described the 2nd operation, with described tungsten oxide layer film forming be: its UPS spectrum is the bossed shape of tool in the combination energy in conjunction with can hang down 1.8～3.6eV minimum than valence band is regional.

18. the manufacture method of organic EL according to claim 16,

In described the 2nd operation, with described tungsten oxide layer film forming be: the differential smoothing of its UPS spectrum have the shape that shows as the function different from exponential function in the whole combination energy zone in conjunction with hanging down 2.0～3.2eV minimum than valence band.

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